I think there is a very good argument that not voting is irresponsible, when it mandates very damaging industrial action that can affect many others.
Certainly. I'm not sure too many would disagree. The question is, whether forcing those who do not wish (or can't be bothered) to vote makes that any better. Again, do you really want up to 50% of those voting only doing so because they're forced? How valid would that be?
The Australian government view seems to be that voting is too important not to care about.
Doesn't make them right. It's a fundamental right to be indifferent too - I would contend forcing people to vote is utterly undemocratic.